On the other hand, studies in 6-hydrodopamine- (6-OHDA-) induced hemiparkinsonian rat models showed that treatment with Levodopa significantly increased MT-III mRNA expression in the striatum on the uninjured side, but did not show any significant effect on the injured side with 6-OHDA; these results suggest that regulation in MT-III mRNA expression may be related to progressive degeneration in parkinsonism [82]. Here, MT3 is linked to Parkinson disease.